[Acute nonspecific pericarditis].

In order to learn the natural history of nonspecific acute pericarditis in our environment, we studied retrospectively 50 patients seen at The Instituto Nacional de Cardiología Ignacio Chávez, between 1972-1985. The clinical history, electrocardiogram, chest x ray, laboratory findings, as well as the outpatient follow-up were analyzed. There was a history of a respiratory or gastrointestinal infection, probably viral in origin, in almost half of the cases (46%). Chest pain was present in 96% of the patients and was the most common symptom. In only half of the patients a pericardial friction rub was heard. A typical S-T elevation was found in 90% of the electrocardiograms. Arrhythmias and conduction disorders were unusual. The echocardiogram showed a pericardial effusion in seven patients and six had a pleural effusion. Only one patient developed signs of cardiac tamponade. None of the patients in this study developed a chronic constrictive pericarditis and there were no deaths. Before or after hospitalization, 14 patients (28%) had multiple episodes of chest pain suggestive of recurrent pericarditis. This study shows that nonspecific acute pericarditis seems to be a self-limited illness with a good prognosis, few recurrences and practically no complications.